Process of bleaching sulfated and sulfonated anionic synthetic detergent compositions and the resulting products



FONATED ANIDNEC SYNTHETIC DETERGENT y COMIQSETIUNS AND THE RESULTING PROD- UCTS Jack Vair Schurman, New York, N. Y., assignor to Colgate-Palmolive Company, Jersey City, N. J., a corporation of Delaware No Drawing. Application Seminar 14, 1954,

I SerialNo.462,-38l

12 Claims. (Cl. 26l)4llll) This invention relates to improvements in bleached non-soap anionic synthetic detergent compositions and to a method of preparing such compositions which eliminates certain undesirable characteristics of these compositions, particularly as regards their tendency towards color reversion on standing. More particularly, the invention relates to such compositions that are of the sulfate or sulfonate type to be described more particularly hereinafter.

One of the disadvantages of present-day non-soap anionic synthetic detergent compositions is that the detergent composition after a brief period of time changes color. Although such a change in color does not in any way afiect the effectiveness of the composition as a detergent, nevertheless the color change lessens itsconsumer appeal.

To overcome this disadvantage of non-soap anionic synthetic detergents, and especially those of the sulfate or sulfonate type, the present invention provides a new process for producing such detergent compositions in such condition that they will retain their original bleached color (and hence their original consumer appeal) over a greatly prolonged period.

Broadly, the invention provides aprocess of bleaching non-soap anionic synthetic detergent compositions in accordance with which an oxidizing agent which will quickly andeffectively bleach the composition 'is added followed by the addition of another oxidizing agent which will prevent the regression of the bleaching eflfect obtained by the first oxidizing agent, therebyresulting in an improved detergent composition in which the tendency towards color reversion is eliminated or at least greatly minimized. More particularly, the present invention is based primarily on the feature of adding a hypohalite to an aqueous solution of a synthetic detergent of the kind indicated. followed by the addition of a peroxide to give a greatly improved non-soap anionic synthetic detergent composition, especially of the sulfate or sulfonate type.

It has been suggested heretofore to add hypohalites to synthetic detergent compositions for the purpose of bleaching same. However, when using hypohalites alone as the bleaching agent the bleaching eifect is retained for only a relatively short period of time.

It is therefore an object of this invention to provide an improved non-soap anionic synthetic detergent composition which will retain its original color over a substantially prolonged period of time in comparison to an otherwise similar composition that has not been treated in accordance herewith.

Other objects and advantages of the present invention will become apparent upon consideration of the following detailed description:

According to the present invention it has been discovered that when a non-soap anionic surface active detergent (and particularly one of the sulfate or sulfonate type) is treated with a'hypohalite followed by a peroxide, a new and improved synthetic detergent results which exhibits all of the desirable properties of the original detergent, such as good rinsing, foaming and deterging ttes Patent ice .2 properties and, in addition, exhibits excellent color re tention properties.

The non-soap anionic synthetic detergent compound, of the sulfate or sulfonate type, may be prepared from organic materials which are applicable for sulfonation (true sulfonation and/or sulfation), especially those having about eight to about twenty-six (and preferably about twleve to about twenty) carbon atoms to the molecule, including fatty oils, unsaturated fatty acids, mineral oils, mineral oil'extracts, monoand diglycerides, partial esters or ethers of polyglycols, esters or ethers of glycols, polyglycols and polyalcohols, aromatic and alkylated aromatic compounds, alcohols, and olefins, coal tar distillates, and numerous other organic compounds and mixtures of compounds. Such compounds can be sulfonated by any of several methods and may form any of several products, depending upon the method of sulfonation employed. The sulfonated or sulfated organic compounds include sulfonated mineral oil; conventional mineral oil refinery sludges; sulfonated mineral oil extracts; sulfonated fatty acids and oils; including sulfonated castor oil, sulforicinoleic acid, sulfonated olive oil, and sulfooleic acid, aliphatic sulfonates and sulfates, including cetyl sulfuric acid, dodecyl acid sulfate, and tetradecanehydroxy sulfonic acid-1,2; aliphatic ether and ester sulfonates including the dodecyl ether of hydroxy ethyl sulfonic acid, the cetyl ether of glyceryl sulfonic acid, tallow monoglyceride monosulfate, coconut oil monoglyceride monosulfate, hydrogenated tallow monoglyceride monosulfate, and hydrogenated coconut oil monoglyceride monosulfate; sulfonates prepared by treatment of organic materials with sulfur dioxide and chlorine in the presence of light followed by hydrolysis of the product; sulfonates prepared by treatment of organic bodies with sulfuryl chloride and an activating agent in the presence of light followed by the hydrolysis of the product; fatty acid amides of amino alkyl sulfonic acids, including lauric amide of taurine and tall oil acid amide of amino glyceryl sulfonic acid; sulfonic acids of naphthenes and naphthenic acids; lingnin sulfonic acids; aromatic and alkylated aromatic sulfonic acids, including naphthalene sulfonic acid, octadecyl benzene sulfonic acid, and dodecyl naphthalene sulfonic acid; the product of a mineral oil extract 'sulfonated while dissolved in liquid sulfur dioxide; and innumerable other organic sulfonic and sulfuric acid derivatives or mixtures thereof. These organic sulfate and true sulfonate compounds include those in which the organic radicals of the molecule are unsubstituted as well as those which contain substituents, such as halogens, halogenoids, hydroxyls, nitrogen-containing groups, acyl groups, acyloxy groups, alkoxy groups, etc.

More particularly, it has been discovered that when a water-soluble non-soap anionic synthetic detergent such as any of those mentioned above is treated with a hypochlorite such as sodium hypochlorite followed by a peroxide such as hydrogen peroxide, a greatly improved detergent composition results which exhibits all of the desirable properties of the original detergent and, in addition, exhibits color retention properties superior to any of the synthetic detergent compositions heretofore known. The detergent is preferably treated while in the form of a solution in a suitable solvent such as water and/or lower alcohol such as isopropanol.

In preparing the improved non-soap anionic synthetic detergent composition of this invention the hypohalite is preferably employed within the range of 0.51.5% and the peroxide should preferably be employed within the range of 0.25-0.9%, both based on the weight of the active synthetic detergent ingredient. The amount of peroxide added is at least sufiicient to react with any residual hypochlorite; for example, according to the v 3 following equation in the case of hydrogen peroxide and sodium hypochlorite:

iron complex and thereby remove a small amount of color caused by the presence of dissolved iron salts.

The solution prior to spray drying is bright and clear. It gives a Lovibond reading (5% inch cell) of 1 Red In view of some possible uncertainty as to the amount of 5 and Yellow and PH (as is) of cfompared.to NaOCl actually consumed in the antecedent step, it is 28 Yellow andPH for the Stamng ff desirable that the H202 be at least chemically equivalent The thus'treated synthetlc detergelft PPWder composltmn to the NaOCl added. This would correspond to the reladoes not rfvert color when mamtamed at a tempera" tionshiP: percent H2O2:(0'46)% NaOCL. ture of 55 to 60 C. over a period of two weeks.

To further illustrate the general process of preparing 10 EXAMPLE II the improved bleached non-soap anionic synthetic deter- In the preparation of synthetic detergent composition s Compositions of the present invention. n evaporated for ultimate bar formation, 5900 lbs. of an evaporated aqueous alcoholic extract of a detergent composition (of aqueous alcoholic extract of the sodium salts of the sulwhich the active ingredientis sodium sulfate monoglycerfuric acid esters of the monoglycerides of the fatty acids 1de estgrs ofhfattydaclds derived from hytflrogenggted cogsoderived from a mixture of hydrogenated coconut oil and nut oi is eate to a temperature of rom to hydrogenated tallow are placed in a tank. 161 lbs. of while stirring a a m er e r t 13 sodium NaOCl (13% C12) are added to the tank following which hypochlorite) is atclldleid 1lwvhile lczmtirilulgg to stlr thegorn- (after a lapse of 510 minutes) 40 lbs. of H202 (10%) 5335i? Anal? n hours it string 253$ if? 11511.3 t.2.13323$5.3;F1213 t."E22. itilffiugiiii$3113? sulfite and tetrasodium pyrophosphate is added. The dative treatment. After approximately one hour of stirscf lutio1111 is then stirred fgr addciltiorial mtinutes. Theering 7 lbs. of N84P207 are added to eliminate iron color a ter t e m1xture may e sprayme to orm a pow or interference and 33 lbs. of NazSOs are added to decomwhich in turn may be extruded under pressure to form 25 pose unreacted free H202. The thus-bleached detergent an improved non-soap anionic synthetic detergent bar K composition is then sprayed into a spray-dryer. The repI(I) IdllC t 1f gesiregd th t f t b d (siulting spragy-drigd gfranular material is then formed into avmg escr1 e e presen 1nven1on 1n 1 s roa er etergent ars y orcing same t rough a plodder in aspects, more detailed examples of procedures in accordotherwise conventional manner, to give a non-soap anionic 33322 132X$333.5351;iElsi?tffisfiii eifi u ifiiif iitl lfiiii iil gfftiisi greatly enhanced $t00 d that this is l l herein for P pose of illus- The following table shows the applicability of the proctration rather than hrmtatton. Percentages are by we1ght ess of the present invention to sill other non-soap anionic throughout the speclficatlon and dams unless otherwlse synthenc detergent materials. It 1nd1cates the Lovibond mc lggatefdn t l 1 t t f 35 reladikrligs for as alkyl aryl SllJlfOIlatC agild arltl alcohol sulfate e o owing wo examp es re ae oprocesses 0 pre- -w 1c are su jecte to t e same eac ing process as paring non-soap amonic synthetic detergent compositions described above and thereafter maintained at a temperato be made into powder and bar form, respectively. ture of 60 C. for a period of three weeks:

Table 7 Before Heating After Heating Detergent Bleached Control Bleached Control (Unbleached) (Unbleached) Alkyl Aryl Sulfonate 11 11/110 Y 50 11/140 Y.- 13.8 R/l38 Y-. 54 R/l-iO Y. Alcohol Sulfates 1.4 R/14 Y 6.3 R/63 Y 2.0 R/20 Y (semi-solids).

1 Sodium salt of benzene sultonic acid alkylated with propylene tetramer. 2 Sodium lauryl sulfate.

EXAMPLE I In the preparation of synthetic detergent composition in powder form, an aqueous alcoholic extract of the sodium salts of the sulfuric acid esters of the monoglycerides of the fatty acids derived from hydrogenated coconut oil is evaporated down to a solids content of approximately 37%. 673 grams of the resulting concentrate are heated in a one-liter, three-necked Morton flask fitted with a mechanical stirrer, a condenser, and a thermometer extending into the liquid. The solution is held at 63 to 68 C. (145 to 155 F.) throughout the process. Stirring is maintained at a moderate rate. When the solution reaches the designated temperature, 17.5 grams of a sodium hypochlorite solution (11% concentration, 7.0% on solids) are added. One half hour later 5.0 grams of hydrogen peroxide (30% concentration, 2.0% on solids) are added. After 1 hours of stirring, a mixture of 5.0 grams of sodium sulfite (anhydrous, 2.0% on solids) and 1.25 grams of tetrasodium pyrophosphate (decahydrate, 0.5% on solids) is added. The solution is then spray-dried to powder form.

The sodium sulfite is added to decompose unreacted free hydrogen peroxide according to the equation:

NazSOs-f-HzOzfiHzO-I-NazSOr The pyrophosphate is added to form a stable, colorless While the above examples have referred to the use of sodium hypochlorite and hydrogen peroxide which are the most common and readily available, it should be understood that any other suitable inorganic hypohalite and inorganic or organic peroxide may be used. For example, the alkaline earth metal hypohalites (such as calcium hypochlorite) and other alkali metal hypohalites (such as potassium hypochlorite) as well as the free acid itself (such as hypochlorous acid) may likewise be used with satisfactory results. All of these reagents are contemplated as falling within the scope of the expression inorganic hypohalite. Moreover, the sodium sulfite may be replaced by other alkali metal sulfites such as potassium sulfite and the tetrasodium pyrophosphate may be replaced by other phosphates including sodium tripolyphosphate and sodium hexametaphosphate as Well as any of the corresponding potassium phosphates.

The time required for adequate bleaching is, generally speaking, a function of the temperature of operation, and both may vary over rather wide limits. In the particular working examples given above, the sulfated monoglycerides are bleached at temperatures of the order of 63 to 68 C. because of their tendency to hydrolyze at higher temperatures; however, more rapid treatment at higher temperatures is feasible with detergents which are stable at the given higher temperatures.

Summarizing, the present invention is based upon the discovery of a process of adding a hypohalite and a peroxide to a non-soap anionic synthetic detergent composi tion to form an improved synthetic detergent composition which will retain its original color over a greatly prolonged period of time.

While the invention has been described in terms of preferred embodiments thereof, it is to be understood that cohsiderable variations in the details disclosed may be made without departing from the true scope and spirit of the invention. Accordingly, the invention is to be limited only bythe claims set forth hereinafter.

' What is claimed is:

. 1. A process of bleaching sulfated and sulfonated anionic synthetic detergents which comprises adding an inorganic hypohalite to a solution of such a detergent followed by adding a peroxide to said solution.

2'. A process of bleaching sulfated and sulfonated anionic synthetic detergents which comprises adding an alkali metal hypochlorite to a solution of such a detergent followed by adding hydrogen peroxide to said solution to destroy excess C.

3. A process of bleaching sulfated and sulfonated anionic synthetic detergents which comprises adding an alkali metal hypohalite to a solution of such a detergent followed by adding a peroxide to said solution, said solution being maintained at an elevated temperature.

4. A process of bleaching sulfated and sulfonated anionic synthetic detergents which comprises adding sodium hypochlorite to a solution of such a detergent followed by adding hydrogen peroxide to said solution, said solution being maintained at a temperature of from about 63 to 68 C.

5. A process of bleaching sulfated and sulfonated anionic synthetic detergents which comprises adding from about 0.5 to 1.5% of an inorganic hypohalite to a solution of such a detergent followed by adding from about 0.25 to 0.9% of a peroxide to said solution.

6. A process of bleaching sulfated and sulfonated anionic synthetic detergents which comprises adding from about 0.5 to 1.5% of sodium hypochlorite to a solution of such a detergent While stirring followed by adding about 0.25 to 0.9% of hydrogen peroxide to said solution while stirring, said solution being maintained at an elevated temperature.

7. A process of bleaching a non-soap anionic synthetic detergent composition comprising alkali metal salts derived from naturally-occurring fats and oils which comprises adding from about 0.5 to 1.5% of sodium hypochlorite to an aqueous solution of said composition while stirring followed by adding from about 0.25 to 0.9% of hydrogen peroxide to said solution while stirring, said solution being maintained at a temperature of from about 63 to 68 C. in the meantime.

8. A process of bleaching a non-soap anionic synthetic detergent composition comprising sodium salts of the sulfuric acid esters of the monoglycerides of the fatty acids from hydrogenated coconut oil which comprises adding from about 0.5 to 1.5 of sodium hypochlorite to a solution of said composition while stirring followed by adding from about 0.25 to 0.9% of hydrogen peroxide to said solution while stirring, said solution being maintained at a temperature of from 63 to 68 C. in the meantime.

9. A process of bleaching sulfated and sulfonated anionic synthetic detergents which comprises adding from about 0.5 to 1.5% of an inorganic hypohalite to an aqueous solution of such a detergent while stirring, adding from about 0.25 to 0.9% of a peroxide to said solution while stirring, and subsequently adding an alkali metal sulfite and an alkali metal phosphate to said solution.

10. A process of bleaching sulfated and sulfonated anionic synthetic detergents which comprises adding from about 0.5 to 1.5 of an inorganic hypohalite to a solution of such a detergent while stirring, adding from about 0.25 to 0.9% of a peroxide to said solution while stirring, and subsequently adding a mixture of sodium sulfite and tetrasodium pyrophosphate to said solution.

11. A bleached synthetic detergent composition as produced by the process of claim 1.

12. A bleached synthetic detergent composition as produced by the process of claim 9.

References Cited in the file of this patent UNITED STATES PATENTS 1,861,513 Taylor June 7, 1932 2,049,975 Reichert et a1. Aug. 4, 1936 2,165,270 Kaulfmann July 11, 1939 2,349,514 Moyer May 23, 1944 2,738,365 Sylvester Mar. 13, 1956 OTHER REFERENCES McCutcheon: Synthetic Detergents, page 141 (1950). 

1.A PROCESS OF BLEACHING SULFATED AND SULFONATED ANIONIC SYNTHETIC DETERGENTS WHICH COMPRISES ADDING AN INORGANIC HYPOHALITE TO A SOLUTION OF SUCH A DETERGENT FOLLOWED BY ADDING A PEROXIDE TO SAID SOLUTION. 